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Groups > comp.lang.python > #16833

Re: Misleading error message of the day

Date 2011-12-08 16:03 +0100
From Jean-Michel Pichavant <jeanmichel@sequans.com>
Subject Re: Misleading error message of the day
References <roy-9DEDD9.09233308122011@news.panix.com>
Newsgroups comp.lang.python
Message-ID <mailman.3415.1323356627.27778.python-list@python.org> (permalink)

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Roy Smith wrote:
> I just spent a while beating my head against this one.
>
> # Python 2.6
>   
>>>> a, b = 'foo'
>>>>         
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
> ValueError: too many values to unpack
>
> The real problem is that there's too *few* values to unpack!  It should 
> have been
>
> a, b = 'foo', 'bar'
>
> I understand why it's generating the exception it does (the string is an 
> iterable), but man, did that message throw off my thought processes and 
> lead me down some totally bogus debugging paths.
>
> It's an unusual case to want to unpack a string.  Maybe the message 
> should changed to "too {many, few} values to unpack (are you sure you 
> wanted to unpack a string?)" if the RHS is a basestring?
>   
string are iterable, considering this, the error is correct.

Values to unpack in 'foo' are 'f', 'o', 'o'

 > a,b,c = 'foo'

 > print a,b,c
f o o


JM

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Thread

Misleading error message of the day Roy Smith <roy@panix.com> - 2011-12-08 09:23 -0500
  Re: Misleading error message of the day Andrea Crotti <andrea.crotti.0@gmail.com> - 2011-12-08 14:39 +0000
  Re: Misleading error message of the day Chris Angelico <rosuav@gmail.com> - 2011-12-09 01:40 +1100
  Re: Misleading error message of the day Robert Kern <robert.kern@gmail.com> - 2011-12-08 14:47 +0000
    Re: Misleading error message of the day Roy Smith <roy@panix.com> - 2011-12-08 07:30 -0800
      Re: Misleading error message of the day Tim Chase <python.list@tim.thechases.com> - 2011-12-08 11:41 -0600
    Re: Misleading error message of the day Roy Smith <roy@panix.com> - 2011-12-08 07:30 -0800
  Re: Misleading error message of the day Jean-Michel Pichavant <jeanmichel@sequans.com> - 2011-12-08 16:03 +0100
    Re: Misleading error message of the day Roy Smith <roy@panix.com> - 2011-12-08 07:33 -0800
      Re: Misleading error message of the day Jean-Michel Pichavant <jeanmichel@sequans.com> - 2011-12-08 20:49 +0100
      Re: Misleading error message of the day Ethan Furman <ethan@stoneleaf.us> - 2011-12-08 12:13 -0800
      Re: Misleading error message of the day Lie Ryan <lie.1296@gmail.com> - 2011-12-09 12:46 +1100
        Re: Misleading error message of the day alex23 <wuwei23@gmail.com> - 2011-12-08 20:57 -0800
          Re: Misleading error message of the day Lie Ryan <lie.1296@gmail.com> - 2011-12-11 10:41 +1100
      Re: Misleading error message of the day Jean-Michel Pichavant <jeanmichel@sequans.com> - 2011-12-09 11:03 +0100
        Re: Misleading error message of the day Roy Smith <roy@panix.com> - 2011-12-09 09:43 -0500
      Re: Misleading error message of the day Ethan Furman <ethan@stoneleaf.us> - 2011-12-09 09:39 -0800
    Re: Misleading error message of the day Roy Smith <roy@panix.com> - 2011-12-08 07:33 -0800
      Re: Misleading error message of the day Grant Edwards <invalid@invalid.invalid> - 2011-12-08 18:10 +0000
        Re: Misleading error message of the day alister <alister.ware@ntlworld.com> - 2011-12-08 20:58 +0000
          Re: Misleading error message of the day Chris Angelico <rosuav@gmail.com> - 2011-12-09 08:17 +1100
        Re: Misleading error message of the day Roy Smith <roy@panix.com> - 2011-12-08 20:19 -0500
        Re: Misleading error message of the day Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-09 02:07 +0000
          Re: Misleading error message of the day Chris Angelico <rosuav@gmail.com> - 2011-12-09 14:46 +1100
            Re: Misleading error message of the day Roy Smith <roy@panix.com> - 2011-12-08 23:44 -0500
  Re: Misleading error message of the day Heiko Wundram <modelnine@modelnine.org> - 2011-12-08 16:16 +0100
    Re: Misleading error message of the day Roy Smith <roy@panix.com> - 2011-12-08 07:42 -0800
      Re: Misleading error message of the day Heiko Wundram <modelnine@modelnine.org> - 2011-12-08 16:50 +0100
        Re: Misleading error message of the day Roy Smith <roy@panix.com> - 2011-12-08 10:42 -0800
          Re: Misleading error message of the day Benjamin Kaplan <benjamin.kaplan@case.edu> - 2011-12-08 13:57 -0500
          Re: Misleading error message of the day Ethan Furman <ethan@stoneleaf.us> - 2011-12-08 11:09 -0800
          Re: Misleading error message of the day Benjamin Kaplan <benjamin.kaplan@case.edu> - 2011-12-08 14:38 -0500
          Re: Misleading error message of the day Ethan Furman <ethan@stoneleaf.us> - 2011-12-08 12:09 -0800
        Re: Misleading error message of the day Roy Smith <roy@panix.com> - 2011-12-08 10:42 -0800
      Re: Misleading error message of the day Andrea Crotti <andrea.crotti.0@gmail.com> - 2011-12-08 15:55 +0000
      Re: Misleading error message of the day Chris Angelico <rosuav@gmail.com> - 2011-12-09 03:21 +1100
      Re: Misleading error message of the day Robert Kern <robert.kern@gmail.com> - 2011-12-08 19:57 +0000
    Re: Misleading error message of the day Roy Smith <roy@panix.com> - 2011-12-08 07:42 -0800

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